Already, quite a lot of toys are available that comprise flywheels, and it is also known to use flywheels in toys to create various gyroscopic effects.
U.S. Pat. No. Re. 30,299 describes a toy car comprising a horizontally disposed flywheel capable of creating various gyroscopic effects on the toy car. While the flywheel rotates, the car may turn about its rear fender, topple onto two of its wheels and move forwards on two wheels until it topples onto all four wheels and moves further ahead.
U.S. Pat. No. 6,676,476 B1 describes a figure including a freely rotatable flywheel mounted within the figure such that the flywheel has a predetermined orientation. A pinion gear is secured to the flywheel and a guide post is positioned a distance away from the pinion gear to form a channel therebetween through which a rack gear can be used to rotate the flywheel and thereby move the figure. In different embodiments of the invention concerned, the vehicle may be eg a skateboard, a scooter, a bicycle, or a car.
US 2005/0215172 A1 shows a four-wheeled car. The car has a securely integrated wheel that is connected to the wheels and coupling stubs.
However, in many cases it is desirable to increase the scope for variations.